You don't say what kind of work you will be looking for. if you want to teach in mainstream schools, then you can look up the school holidays for any country on the Internet. Most other forms of employment for English teachers such as in high street cram schools and language institutes, in-company, etc, obviously don't depend on the academic cycle and will have openings at any time of the year. You can get a good feel for the employment market by watching the adverts on all the various TEFL job sites.